Manufacture of articles from powdered materials



- Patented Aug. is, 1938 UNITED STATES.

PATENT OFFICE Gregory J. Comstock, Fairfield, Conn., assignor to Handy &Harman, Bridgeport, Conn., a corporation of New York No Drawing.

Application August 10, 1935, SeriaLNo. 35,631

8 Claims. (or 73-22) This invention relates generally to the manufactureof articles from powdered metals and more particularly to themanufacture of articles such as silverware jewelry and objects of artfrom precious metals or mixtures of precious metals with base metals.The invention isparticularly described in connection with the use ofpowdered precious metals such as silver, gold, platinum, iridium,palladium and the like. Among the base metals which may be used inconjunction with the precious metals are copper, nickel, zinc, antimony,cobalt, molybdenum, tungsten, titanium, tantalum, iron, and alloys ofthese metals.

Powdered metals are used for a wide variety of purposes, among which maybe mentioned the production of porous material for use as bearings, andthe production of cutting tools where thepowdered materials employed aregenerally the refractory metals or their carbides. The present inventionrelates to the production of solid, that is, non-porous, articles ascontrasted with those suitable for'bearings. By the term non-porousYImean compositions which are relatively free from pores as compared withthose compositions suitable for bearings and which are usually madeporous intentionally 'so as to hold a lubricant.

The non-porous compositions of the present invention are those which aresufiiciently dense so that they do not work materially dififerently fromthe melted and cast alloys and have strengths and other properties notmaterially different from cast alloys. The metals which I employ are theprecious metals either alone or in conjunction with smaller amounts ofbase metals as contrasted with compositions containing the refractorymetals such as tungsten or tantalum or their carbides in large amount,which compositions are employed for the production of cutting tools,drawing dies and the like. By the use of powdered metals, articles canbe made of various compositions which would not be possible to make byamelting andcasting process due to the fact that in such melting andcasting proceases the composition in many cases is limited by thetendency oi the metalsemployed to alloy with each other in diflerentproportions.

. The present invention is applicable to the proso as to form thedesired design on the presintered base. Lines, lettering or designs maybe applied in this way in a very simple manner. Powdered silver is thensprinkled over the presintered base and the excess powder which does 5not stick to the adhesive is shaken off and the base with the powderedsilver adhering thereto in the desired design is placed in a mold andhot pressed. In the hot pressing operation, a highly polished metalplunger thinly coated with graphite or lamp black is used to prevent theplunger sticking to the applied powder. The pressure employed in the hotpressing step may be, for example, 2000-4000#/sq. in. in order toconsolidate the powder and densify the presintered base.

Powdered metal may be applied to a cast and rolled base rather than to apresintered base by the method just described of applying powdered metalto an adhesive applied in a design to a base, and the base with theapplied powder may then be subject to .hot pressing as previouslydescribed. A design of copper inlaid on a rolled sheet of sterlingsilver has been successfully made according to this process.

For purposes of illustration I have described the invention particularlywith reference to the use of silver and copper. It will be understood,

however, that other combinations of powdered and sintering the powderedmaterial and consolidating it with the sintered body by the a plicationof heat and pressure.

2. The method of forming an inlaid article, which -comprises forming asintered body from powdered material by the simultaneous application ofheat and pressure, applying powdered material to the sintered body bythe use of an adhesive, and sintering the powdered material andconsolidating it with the sintered body by the application of heat andpressure.

3. The method of forming an inlaid article, which comprises forming asintered body from powdered materialby the simultaneous application ofheat and pressure, applying powdered material to the sintered body bythe use of an adhesive, and sintering the powdered material andconsolidating it with the sintered body by the simultaneous applicationof heat and pressure greater than the heat and pressure employed informing the sintered body to which the powdered material was applied.

4. The method of forming an inlaid article, which comprisessimultaneously heating and pressing powdered material to form a sinteredbody, applying an adhesive to the sintered body in the desired design,applying powdered material to the sintered body and shaking off theexcess which does not adhere to the adhesive, and subjecting thesintered body with the powdered material adhering thereto in the desireddesign to the simultaneous application of heat and pressure greater thanthe heat and pressure employed in forming the sintered body.

5. The method of forming an inlaid article, which comprises applyingpowdered material in a design to a base by the use of an adhesive, andsubjecting the base and appliedpowdered material to simultaneous heatand pressure sufficient to sinter and consolidate the design with thebase.

6. The method of forming an inlaid article, which comprises applyingpowdered precious metal in a design to a base by the use of an adhesive,and subjecting the base and applied powdered precious metal tosimultaneous heat and pressure sumcient to sinter and consolidate thedesign with the base.

7. The method of forming an inlaid article, which comprises applyingpowdered material in a design to a cast and rolled base by the use of anadhesive, and subjecting the base and applied powdered material tosimultaneous heat and pressure suflicient to sinter and consolidate thedesign with the base.

8. The method of forming an inlaid article, which comprises applyingpowdered precious metal in a design to a cast and rolled base by the useof an adhesive, and subjecting the base and applied powdered preciousmetal to simultaneous heat and pressure sufllcient to sinter andconsolidate the design with the base.

GREGORY J. COMSTOCK.

